# In-orbit Calibrations of the Ultra-Violet Imaging Telescope

## TL;DR

This paper presents the results of in-orbit calibration procedures for the Ultra-Violet Imaging Telescope (UVIT) onboard ASTROSAT, detailing its performance across multiple ultraviolet and visible channels.

## Contribution

It provides the first comprehensive in-orbit calibration results for UVIT, demonstrating its imaging capabilities and calibration accuracy in space.

## Key findings

- UVIT achieved spatial resolution better than 1.8 arcsec.
- Calibration confirmed the instrument's performance across all channels.
- Results enable reliable scientific observations with UVIT.

## Abstract

The Ultra-Violet Imaging Telescope (UVIT) is one of the payloads in ASTROSAT, the first Indian Space Observatory. The UVIT instrument has two 375mm telescopes: one for the far-ultraviolet (FUV) channel (1300--1800\AA), and the other for the near-ultraviolet (NUV) channel (2000--3000\AA) and the visible (VIS) channel (3200--5500\AA). UVIT is primarily designed for simultaneous imaging in the two ultraviolet channels with spatial resolution better than 1.8 arcsec, along with provision for slit-less spectroscopy in the NUV and FUV channels.The results of in-orbit calibrations of UVIT are presented in this paper.